Process of treating coffee



Patented Aug. 19, 1952 PROCESS OF TREATING William. is." nalaiMialana, Mien, assignor to Verdurin CompanygDetroit, Mich., a corporat onofMichigan This invention relates. to; a process; omreating coffee and to a roasted 'cofieetprodu'ct? of improved quality. 7 v p M Broadly considered,. the invention .,com'pre-- hends" the concept of roasting coffee in the pres',

ence of or in contactwith'fanon toxicjporphyrin type compoundjwhich has a" selective, beneficial-x actiononjcertain'undesirableconstituents of the coffee bean vtothereby.produce; a product of en--' hanc'ed 'quality.

the 'plantworld the catalyst chlorophyll existsin' two'well. defined" forms, (QstHizosNlMgl and chlorophyll-b (C55HroQsN4Mg).J c

in the -ratio' of abOut S to -1 respectively.-- The former readily undergoes oxidation into the latter in the presence of air and-thelatter readily undergoes reduction" into the former through the agency of carotenes and similar deoxidants-al- Ways present wherever chlorophyll is present." In the presen-ce of sunlightthecoordinated function of chlorophylls-and "carotenes sufiices to; reduce carbonic acid of the atn'iosph'e're into the vast array 'of' organic compounds on' earth.

The interplay of oxidative and reductive'agencies within the leaves and parts of growing plant continues through the life of plant except for periods of dormancy-among the -deciduous.- Following dormancy I a new rebirth of chlorophyll within the budding leavesreinvigorates the-oxidative-reducti-ve cycleJ- l Naturally the fruits of 7 many plants carry their Spe ific-share of these catalysts, but in the ripening' of gfruit muchgif not all,=*of=the chlorophyll is destroyed; 1 witness, for examplegthe green-apple ripening into red.--

Inmu'chthe same manner the green berry; in-

ripening, is observed to undergor a change in color toward the yellow, brownand redz' --It "is further tobe-n'oted that certain fruits: of their own; and

in green' status, are ableby merely standing in presence of air," to undergo oxidationto-the point of ripening; witness, for :example, the green banana transformed into the :yellowl ripez and mellow fruit. Theichlorophyllsin :the banana-,zin: both flesh and skin, has served as catalyst for I when {roasted before the green berry. has turned brown, and to such ex that iajbe'verage made fromthe-roasted, bean s 'mg'my palatable, or

course; the quantity of chlorophyllin the roasted chlor ophyll a J No Dra wing; Application July 11, 1949,

; Serial N0. 104,139

ceedingly small content. of chlorophyll willplay its role as oxidativecatalyst increasingly with rise in temperature, or up to point of its decomposition. Onthis basis it has now been determined that chlorophyllmay play a beneficial role in destroying small portions, of chlorogenic acid and trigonelline, two of the undesirable factors always present .in coffee. At the same time chlorophyll appears to beincapable of destroying the caffeine content of coffee. These facts, as will be appreciated,makepossible the producing of an improved beverage. V I

As'isknown to thosev skilled in the art, the degree and. duration of roasting coffee beans have muchv to. do..,with-final. composition of roasted bean. Where. over-roasting is carried on there is found to be) present somewhat less trigonelline 'underthe normal content of approximately 1 per cent.. of same in ordinary roastedcoffee. 80, likewise; the content of chlorogenic'acid in. highly roasted. coffee isfno more than-% of the usual 4-. to. 5 'percent. ofsame in ordinary roasted coffee. in all "cases theflcaffeine content of about 1 per cent. by weight remains constant for lightly roasted or highly roasted. coffee so long as there has occurred noburningthat leads'to its destruc- There have beenmany. attempts to improve the beverage qualities of cofi'e'lextract. and at the same time to remove'jcertain'of the undesirable components. Most we'llrknown here is Sanka,

from a coffee beanth'a't has'sufieredthe-loss of the greater-portion ,offits'caffeine through .extraction with trichl'o'roethylene or other solvents. As caffeine is a heart. stimulant, "the newly pro-. duced Sanka can v scarcelyincite sleeplessness. But thedeleterious component of coifee isnot caffeine; it is the alkaloid trigonelline, and .anhydride of the toxic No-methyl-hydroxy-nicotinicacid. So, likewise; chlorogenic acid through its hydrolytic products; caifeicand. quinicl acids; is more than likely to set up points ofintestinal irritation j i 1 V It is now found that. the impregnation of green coffee'beanswith an additional quantity of chlorophyll amply suflicest for; a more extensive catalytic oxidation of the contents!v of the bean withoutmaterially'affecting the content of the caffeine, so' desirable as stimulating, factorfin coffee, beverages. "Inparticular. we note thatthe deleterious trigonelline and chl'orogen icacidflarc markedly reduced in percentage content. Fur

thermore, as may well have been inferred, the additional oxygenative action serves well to couple butyl, furfuryl and other mercaptans into the polysulphide stage-or that stage definitely contributive to coffee aroma. So marked is this that if sufficient chlorophyll can be evenly distributed withinthe green bean the oxidative processes accompanying roasting can be carried out in shorter time and often times at lower temperatures; all of which makes possible a less toxic coffee beverage and yet one with an enhanced aroma. Naturally, too long a roasting with or without chlorophyll will destroy all.

aroma; hence 5 to minutes roasting is the general practice.

The term chlorophyll, as herein employed,

methine groups linked alternately into a 16 membered. carbon-nitrogenring known as porphin wherein derivatives of such, known as porphyrins, comprising the naturally occurring haeme and chlorophyll, ,are primarily concerned in this study. A The haeme derivativescarry a metallo-complex of iron; whereas the chlorophyll derivatives carry a metallo-complex of magnesium. Furthermore, many of these compounds, as haeme and ordinary chlorophyll, are insoluble in water. In the purview of this invention, preferably soluble or solubilized' forms of these porphyrin compounds are employed. This, by reason of the fact that as deep a penetration of the green bean must be effectuated if we would attain the highest degree of reaction within the bean upon roasting. I

The union of haeme'with the protein globin leads to the soluble haemoglobin." But of most striking note this globin confers upon the haeme molecule the property of reacting reversibly with oxygen without suffering a change in valence of its ferrous iron-complex into the ferric state as present in haematin. In general haeme and haematin derivatives possess aperoxidase actiity. The enzyme peroxidase occurs in many,

plants and serves ideally in an oxidative capacity wherever such plants are subject to chemical changes, as for example, in the roasting of coffee beans.

In the case of chlorophyll there is readily securable a water-soluble form simply by hydrolyzing away the phytyl group to yielda. type of compound known as a chlorophyllide; a little further hydrolysis eliminates the methyl group attached to the remaining carbomethoxyl such that the end-product is no longer an ester but a free acid usually in the formof an alkali salt; this product is known as a chlorophyllin. Both'chloro phylide and chlorophyllin are equally as reactive toward oxygen as is the insoluble chlorophyll. Indeed the magnesium-complex of all of these compounds can also be removed by acid treatment whereupon the resulting pheophorbins and pheophytins respectively come to hand.

They too are equally as reactive toward oxygenv In a recent patent to Sidney Musher, U'. S. P. 2,198,207 of April 23, 1940 (see also earlier U. S. P. 2,026,697 of January '7, 1936), there is presented a means for stabilizing roasted coffee simply by spraying hot coffee beans, toward the end of roasting process, with powdered green coffee in aqueous dispersion or suspension, and even with extract of the green beans. Of course, this treatment introduces the normal proportion of undesirables, chlorogenic acid and trigonelline, and cannot function in any such capacity as is required in the present invention. It is well knownthat chlorophyll does not yield readily to extraction from green vegetable matter by alcohol and water; much less, then, can we expect a coffee bean of: practically no chlorophyll con tent to yield up any chlorophyll whatsoever.

Thus the overall content of caffeine, chlorogenic acid and trigonelline in the resulting beverage from above-cited patent cannot differ from that generally found in roasted coffee; the advantage claimed rests entirely'on attainment of greater stability against oxidation.

With the purview of the present invention thereis no concern for stabilization. The sole purpose here is toraise the, OXidiZlIlg power to a point guaranteeingthereduction of chlorogenic acid and trigonellinea's' present, throughout the bean. The addition of. green coffee or its total extracts to roasted coffee is the equivalent of roasting coffee by successive stages. The present invention proposes to, carry the oxidant. chlorophyll into the innermost interstices of the green bean so as to efiect'a's'complete an oxidation as possible in the subsequent roasting. Hereby the undesirable components that are readily oxidizable will be destroyed. Though numerous oxidantshavebeen tried the best by far comprise the porphyrins, totally non-toxic and readily de-' stroyed in the process-itself; 1 On the other hand an application .of chlorophyll and other-porphyrins to the roasted ,bean is found to contribute to a disturbance in balance between the polysulphides supplying the coffee aroma, and increases possibility; to .staleness in resulting beverage; ,v j 1 I 1 In carrying out the-invention,-porphyrinderivatives were introduced into green coffee beans as well also as in roastedcofi'ee beans. Analytical results indicated a considerable decomposition of only the more; readily oxidizable components, such as chlorogenic acid (inclusive of its constituent parts, caffei jand quinic acids) 7 and trigonelline, but not appreciatively of caffeine and the polysulphides, -The result isthe enhancement of the final product for beverages in all cases where ;the1green-;beans were treated, but in the case ofroasted beans only=when roasting had been scarcelystartedw? r y f The coffee bean selected was thatof-Brazilian yp ow as yzing in green state'for 0.96 per cent. caffeine; 5.60 per cent. :chlorogenic acid; and 1.20 per cent-trigonelliner- The eminent utility of the invention will be appreciated from a consideration "of the following examples: r-ti 1 Example 2 XQWP Q; 1 .was e e tede jhere Jlllie j uahfi rqfheemgeleb I a ubsti u ed .a o the. .p qph rh n The I f e l t were Pr ally en cal th .ose of: Exam le 1: caffeine 1 per cent., chlorogenic acid 3.4 per cent., and trigonelline 0.7 per cent.

Example 3 Example 1 was repeated save here an equivalent quantity of sodium iron chlorophyllin in green powder of 65% concentration was used (0.3 gram). The green powder was dissolved in 50 cc. of distilled water as in Example 1 and applied to one pound of gently dried green Brazilian coffee beans. After roasting the product analyzed for caffeine 1.02 per cent., chlorogenic acid 3.38 per cent., and trigonelline 0.6 per cent.

Example 4 Example 5 To one pound of the aforementioned green Brazilian coffee beans dried to per cent. moisture was added 0.7 gram of potassium magnesium chlorophyllin in green powder of 25 per cent. concentration dissolved in 50 cc. distilled water and I 5 cc. of ethyl alcohol added thereto to increase wetting action on beans. After roasting for 10 minutes the coffee analyzed for caffeine 0.9 per cent., chlorogenic acid 2.5 per cent., and trigonelline 0.2 per cent.

Example 6 Afterwhich the porphyrin is chlorophyllin.

Example 5 repeated with the green coffee beans cut into halves to increase penetration. After roasting the coffee analyzed for caffeine 0.9 per cent., chlorogenic acid 1.6 per cent. and trigonelline 0.11 per cent.

Example 7 e'tration of the green abean by. the oxidant: solution. The. :crackedtgreen .beansjarahere' tolbe preferred. -1. The.- addition'zoi; a .twetting :agent is generally.desirable.zbutiscarcelyi soxwhentcracked beans.--.are employedzxOrdinaryethyl alcohol was-found; most satisfactory: as wetting agent. Glycols and other non-toxic wetting agent may beiused; Inalllcases; thesolutionzof .theoxidant should beadjustedato alkalinityislightly abovepI-L 7 0n. thefaeid.side: it: is-;.necessary'.- toemploy. specificzsolventsto effect.satisfactoryzpenetration. Ill'ieernploymentaof'0.045igram.-of chlorophyllin to 1 9 :pou'ndmf green .cofiee bean .is'zequivalent '.to; of 1 per cent. chlorophyllzcontent imbean tobev roasted. moreithan timestheouantity of chlorophyll generally present as maximum in green coffee beans. In some instances as much as 2 per cent. of chlorophyll content was employed merely to induce greater penetration of bean by the concentrated solution. When quick roasting is desirable at higher temperatures, the presence of increased chlorophyll is desirable.

Likewise it is found advantageous at times to accept small quantities of the generally accompanying carotenes with the chlorophyll employed. The carotenes aid in the stabilizing of the chlorophyll itself, especially valuable in the initial stage or heating-up of the coffee beans, as well as in promoting the oxidation steps.

It is also possible to employ insoluble chlorophyll itself if such is solubilized by the presence of certain solvents such as alcohol and acetone. Penetration of the green bean is all the more speedy, but a solvent recovery system is here called for.

While a preferred modification of the invention has been described, it is to be understood that this is given to illustratethe underlying principle of the invention and not as limiting the useful scope of the invention to the particular chosen embodiment.

I claim:

1. A method of preparing coffee which comprises impregnating dried green coffee with a solution of non-toxic oxygen-carrying porphyrin and roasting the coffee up to a temperature not substantially in excess of 400 F. for a period of time sufficient to destroy a substantial portion of the chlorogenic acid and trigonelline present in the green coffee.

2. A process in accordance with claim 1 3. A process in accordance with claim 1 in which the porphyrin is a solubilized chlorophyll.

4. A process in accordance with claim 1 in which the porphyrin is a chlorophyllide.

5. A process in accordance with claim 1 in which the porphyrin is pheophorbin.

6. A process in accordance with claim 1 in which the porphyrin is sodium iron chlorophyllin.

'7. A process in accordance with claim 1 in which the porphyrin is potassium magnesium chlorophyllin.

8. A method of enhancing the beverage quality of coffee which comprises incorporating within unroasted coffee a solubilized porphyrin and then roasting the coffee.

9. A method of enhancing the beverage quality of coffee which comprises incorporating within unroasted coffee asolubilized, non-toxic, oxygencarrying porphyrin to no more than approximately 2% by weight of the coffee and then roasting the coffee. I

10. .A process in accordance with claim 9 in which the porphyrin is a. solubilized chlorophyll.

11. A process in accordance with claim 9 in 1'5.-;A methodio'f reducing the trigonehin m.- 15

tent of coffee which cdmprises'roasting the coffee in the presence of a 'solubilized porphyrin. 'mwILLIAMJ HALE.

V REFERENCES CITED The following references are of record in the file of'this patent: V

UNITED STATES PATENTS Number Name Date 1,313,209 RObiSOh Aug. 12, 1919 1,822,227 Lendrich'; Sept. 8, 1931 1,956,290 Henser -5 Apr. 24, 1934 2,341,723

Kennedy Feb'.'15, 194A: 

1. A METHOD OF PREPARING COFFEE WHICH COMPRISES IMPREGNATING DRIED GREEN COFFEE WITH A SOLUTION OF NON-TOXIC OXYGEN-CARRYING PORPHYRIN AND ROASTING THE COFFEE UP TO A TEMPERATURE NOT SUBSTANTIALLY IN EXCESS OF 400* F. FOR A PERIOD OF TIME SUFFICIENT TO DESTROY A SUBSTANTIAL PORTION OF THE CHLOROGENIC ACID AND TRIGONELLINE PRESENT IN THE GREEN COFFEE. 